A sheet of BCC iron 3.2-mm thick was exposed to a carburizing atmosphere on one side and a decarburizing atmosphere on the other side at 725C. After having reached steady state, the iron was quickly cooled to room temperature. The carbon concentrations at the two surfaces were determined to be 0.015 and 0.0070 wt%. Calculate the diffusion coefficient if the diffusion flux is 1.6 10-8 kg/m2-s, given that the densities of carbon and iron are 2.25 and 7.87 g/cm, respectively. Hint: Use Equation 4.9a-that is, for this problem c :-( X 103 Cc Cro " to convert concentrations from weight percent carbon to kilograms of carbon per cubic meter or iron